It is known to monitor the movement of an object including a person by means of a tag attached to the object, and a plurality of tag readers located in an area to be monitored. Such areas include the passenger portions of an airport environment, baggage handling areas for passengers, the floor area and conveyor systems in a warehouse, package handling for mail distribution, retail premises and other environments.
After the weather, the second largest delay for airlines is passengers arriving late at the departure gate. With no visibility into the whereabouts of passengers after they have checked-in, some people have proposed attaching Radio Frequency Identification (RFID) tags to boarding cards or frequent flyer cards and using a network of RFID readers around the airport to track a passenger's location. Most prior art systems use RFID readers as a beacon, whereby passengers is detected when they are in the proximity of the reader, but when they are out of range, they are “lost” to the system.
Some have suggested an enhancement to this, using zones to track passengers, where a reader is placed at every entry and exit point to a zone, to know accurately which area the passenger is in. However, none of the prior art systems based on zones appear fully to have explored the advantages that are made possible by such a system.
Some have suggested that knowing the departure time and gate of a flight, and knowing where a passenger is now, and how long it takes to get from that passenger's current location to the gate, you can warn passengers at risk of being late.
However, no one has explained in detail how it is possible to create timing information effectively in a large airport, and there is no consideration of other “real world” factors that effect any time of arrival, specifically queue time in bottleneck areas like security.
A summary of relevant background art is set out below.
WO 2003/065257 (KNIGHT) discloses a passenger check-in and monitoring system that uses a memory device in the form of an electronic radio frequency identification tag (RFID tag) containing passenger and travel information which is linked to a passenger travel ticket, passenger boarding card of other personal identity item and passenger luggage including hand luggage. A plurality of antennas is disposed about the airport to detect the movement of RFID tags around the airport complex. KNIGHT further discloses that the airport may be compartmentalised into zones, with antennas located at the entry and exit points of zones enabling airport users to be traced to specific areas within the airport. Problems can arise, however, when an antenna located at the entry and exit points of a zone fails to detect the passage of a tagged object into or out of a zone and, particularly in applications with a significant number of interlinked zones, the system can become confused.
U.S. Pat. No. 6,338,041 (FUJITSU) discloses a passenger management system having a boarding processing system with a plurality of tag readers and speakers connected to an automatic broadcasting unit each located in a plurality of areas into which a premises of an airport is divided. If there is found a remarked boarding card with which the check-in has been completed at a checking counter but boarding has not yet been confirmed, the tag readers ale successively actuated from a gate counter and an area among said plurality of areas in which said remarked boarding card is present is determined based on the signal received by said tag readers Such systems have the disadvantage that passengers are identified as late only when they fail to turn up at the boarding gate, when it may be too late to locate them in time for the scheduled departure.
WO 03/075216 (INTERNATIONAL AIRTAG) discloses an airport communication system having a tag affixed by a clip to each passenger en route between check-in and boarding. Each tag transmits an identifier on a particular RF channel with a short range and the location of a transponder which receives the transmission indicates passenger location. A server correlates tag and passenger and identifies and generates alerts if alert conditions are met such as excessive distance from a boarding gate at a particular time.
WO 01/92910 (WALKER) discloses a method and apparatus for determining the location of a plurality of users. It is disclosed to use radio frequency communications and that the tag could have an LCD display screen and that the tag could be used to remind passengers that a flight has started boarding or that boarding is about to close, before the passenger is late
US 2002/0134836 (CASH) discloses an event driven baggage management system whereby readers are used to detect and monitor the location of tags attached to baggage as the baggage moves from the point at which the traveller drops off the baggage to the point at which the passenger picks up the baggage at a destination location. The system predicts a time (t1) for the object to travel from a first reader to a second reader. If the object is not detected by the second tag reader at time t1 following detection by the first reader, the location status of the tag is deemed uncertain. The document further discloses the sending of notification to a traveller or the carrier when specified baggage events occur.
With reference now to retail supply chains, it is becoming common practice to attach RFID tags to pallets and cases so as to be able to track goods through the supply chain. Today, tracking is at a high level of granularity (e.g. with readers at the doors into and out of a warehouse, so it is possible to know whether or not products are in the warehouse, but not exactly where those goods are in the warehouse).
With the drive towards continuous flow distribution, orders have to be ready to ship at a specific time. With large warehouses/distribution centres preparing orders through a variety of mechanisms (e.g. one order could use a mixture of full-pallet picking using fork-lift trucks, full-case picking using conveyor and sorting systems, and cross-docking of goods), there is a lot of complexity and opportunity for things to go wrong. Often when a problem occurs, the warehouse supervisor only realises when a product is not at the dock door on time, and this is too late to take collective action. So, there is a real advantage in knowing where each item is as it moves towards the dock door, and having the ability to predict problems at the earliest opportunity.
A summary of relevant background art is set out below.
WO 02/082395 (US POSTAL SERVICE) discloses a method and apparatus for tracking and locating a moveable article through geographical areas using electromagnetic signals. An article contains a tag operating as transmitter and receiver. Tag readers in the defined geographical area interact with the tags to track the article An area may be polled by the readers to identify the location of specific objects, for example objects that should be on a departing mail truck.
WO 00/45324 (SENSORMATIC) discloses a method for production and operations management using a read/write RFID tag associated with a product to be processed whereby information may be written to the tag following each of one or more processes performed on the product including a manufacturing process, an inspection process, a shipping process, a warehousing process and a retailing process. The document discloses verifying if the performance is close to the expected or perceived performance by determining a difference between actual performance and programmed or forecast performance of the effective utilization ratio in a warehouse.
WO 01/067127 (ECARGOSERVICE) discloses a method and apparatus that automatically tracks monitors and schedules the shipping of objects through carriers such as delivery trucks, ships or planes. A tracking tag is attached to each shipped object and may incorporate GPS, cellular technology and barcoding as tracking techniques, and sensors such as temperature pressure and noise. Logic rules are applied to tracking information to include or exclude the information. For example the information may be checked against time to see if time between locations is plausible. Periodic checks are also made to see if the object is being transported according to schedule.